The Effect of Granulometry of Carbonaceous Materials and Application Rates on the Availability of Soil-Bound Dichlorodiphenyltrichloroethane (DDT) and Its Metabolites.

Biochars (BCs) and activated carbons (ACs) are well-known carbon-rich materials that are being increasingly studied in environmental sciences for water treatment applications to remediate pollutant sequestration in soil. This study aimed to assess the impact of Sargasso BC particle size and amendment rate on the environmental availability of DDT and DDT metabolites in two distinct Kazakh soils. These two soils were collected in the vicinity of storehouse facilities in Kyzylkairat and Beskainar that store banned pesticides. They presented very distinct concentration levels of DDT and DDT metabolites. Three different types of carbonaceous matrices were tested: Sargasso BC and two commercial ACs (ORBOTM and DARCO©). For the granulometry effect, Sargasso BC was ground, and two particle sizes were tested (<150 µm, >150 µm) and compared to an unground material. Four distinct application rates were tested (0.25, 0.5, 1, and 2% (w/w)). After a three-month maturation period, environmental availability was assessed using an ISO/DIS 16751, part B-modified methodology. Interestingly, the best reductions in DDT environmental availability were obtained with the finest particle size (both ACs and Sargasso BC < 150 µm). More specifically, the effectiveness of the strategy seemed to depend on many factors. Firstly, a clear soil effect was demonstrated, suggesting that the more contaminated the soil, the more efficient this strategy may be. Secondly, the results showed that an increase in the amendment rate improves the immobilization of DDT and DDT metabolites. The sequestration material demonstrated different efficiency values (up to 58 ± 4% for Sargasso BC < 150 µm and 85 ± 4% for DARCO at a 2% application rate). Finally, a clear molecule effect was displayed, demonstrating the following immobilization order: p,p'-DDE > p,p'-DDD > p,p'-DDT > o,p'-DDT.

Genetic Polymorphism in the Amaranthaceae Species in the Context of Stress Tolerance.

The adaptive potential and biochemical properties of the Amaranthaceae species make them promising for introduction into agriculture and markets, particularly in arid conditions. Molecular genetic polymorphism analysis is the most powerful tool for studying plant resources; therefore, the current study aimed to investigate the polymorphisms of allelic variations in the ARF and SOD gene families, as well as the genetic diversity of six Amaranthaceae species, using retrotransposon-based fingerprinting with the multi-locus EPIC-PCR profiling approach. Additionally, the iPBS PCR amplification was employed for genome profiling, revealing variations in genetic diversity among the studied Amaranthaceae samples. The observed genetic diversity in Amaranthaceae species contributes to their enhanced tolerance to adverse environmental conditions. The knowledge about the genetic diversity of genes crucial in plant development and stress resistance can be useful for the genetic improvement of cultivated Amaranthaceae species.

PGPR-driven phytoremediation and physiobiochemical response of Miscanthus × giganteus to stress induced by the trace elements.

The effect of inoculation of Miscanthus × giganteus Greef et Deu by the plant growth promoting rhizobacteria (PGPRs) to the phytoremediation process and physio-biochemical plant's parameters was investigated in soil contaminated with the trace elements (TEs) from the Tekeli mining complex, Kazakhstan. Yeast Trichosporon sp. CA1, strains Rhizobium sp. Zn1-1, Shinella sp. Zn5-6, and Pseudomonas sp. CHA1-4, resistant to Zn and Pb, were isolated from the rhizosphere of M × g when the plant was cultivated in the same contaminated soil. Results illustrated that inoculation improved M × g adaptability to TEs toxicity by increasing the tolerance index to 2.9. The treatment enhanced the aboveground biomass yield by up to 163%, root biomass by up to 240%, chlorophyll content by up to 30%, and Chla/b ratio by up to 21%. Through M × g active growth and development, the peak activity of antioxidant enzymes was observed: activity of superoxide dismutase and glutathione reductase was induced, while the activity of catalase and ascorbate peroxidase was inhibited. Based on bioconcentration and translocation factors it was revealed that PGPRs selectively increased the uptake of TEs or stabilised them in the M × g rhizosphere. Inoculation with PGPRs increased the stabilization of Pb, V, Cr, Co, Ni, Cu, Cd, As, and Ba in the soil and plant tissues. Further research should focus on ex situ experiments using isolated PGPRs.

Phytoremediation of Soil Contaminated by Organochlorine Pesticides and Toxic Trace Elements: Prospects and Limitations of Paulownia tomentosa.

Paulownia tomentosa (Thunb.) Steud is a drought-resistant, low-maintenance and fast-growing energy crop that can withstand a wide range of climatic conditions, provides a high biomass yield (approximately 50 t DM ha-1 yr-1), and develops successfully in contaminated sites. In Kazakhstan, there are many historically contaminated sites polluted by a mixture of xenobiotics of organic and inorganic origin that need to be revitalised. Pilot-scale research evaluated the potential of P. tomentosa for the phytoremediation of soils historically contaminated with organochlorine pesticides (OCPs) and toxic trace elements (TTEs) to minimise their impact on the environment. Targeted soils from the obsolete pesticide stockpiles located in three villages of Talgar district, Almaty region, Kazakhstan, i.e., Amangeldy (soil A), Beskainar (soil B), and Kyzylkairat (soil K), were subjected to research. Twenty OCPs and eight TTEs (As, Cr, Co, Ni, Cu, Zn, Cd, and Pb) were detected in the soils. The phytoremediation potential of P. tomentosa was investigated for OCPs whose concentrations in the soils were significantly different (aldrin, endosulfans, endrin aldehyde, HCB, heptachlor, hexabromobenzene, keltan, methoxychlor, and γ-HCH) and for TTEs (Cu, Zn, and Cd) whose concentrations exceeded maximum permissible concentrations. Bioconcentration (BCF) and translocation (TLF) factors were used as indicators of the phytoremediation process. It was ensured that the uptake and translocation of contaminants by P. tomentosa was highly variable and depended on their properties and concentrations in soil. Besides the ability to bioconcentrate Cr, Ni, and Cu, P. tomentosa demonstrated very encouraging results in the accumulation of endosulfans, keltan, and methoxychlor and the phytoextraction of γ-HCH (TLFs of 1.9-9.9) and HCB (BCFs of 197-571). The results of the pilot trials support the need to further investigate the potential of P. tomentosa for phytoremediation on a field scale.

Evaluation of environmental contamination by toxic trace elements in Kazakhstan based on reviews of available scientific data.

The environmental situation concerning pollution by (eco)toxic and persistent trace elements in Kazakhstan has been investigated by analytical reviews of scientific studies published over the past 20 years reporting concentrations of 10 toxic trace elements (TTE) observed in soil, sediments, or surface water. A database of 62 articles published in Kazakh, Russian, or English covered the majority of the territory of the country for soil and water samples but to a lesser extent for sediments. Reported concentrations were summarized using statistical parameters, then spatialized and finally classified in contamination classes according to local legislation. This analysis revealed some hotspots of TTE in surface waters (Cd and Pb), soil (As), and sediments (Cd and As). Hotspots of less toxic Cu, Zn, and Mn were also detected. Spatialization of results allowed localization of these hotspots close to industrial sites, such as smelters or mining and metallurgic combines. Others have been shown to be close to disused mining sites or landfills with municipal waste. Methodological improvements for further studies have been suggested, such as to integrate more West Kazakhstan or remote areas in sampling campaigns, but also to describe more exhaustively the used analytical methods and to be more attentive to the speciation of the analyzed form of the element. Finally, a management strategy to strengthen a sustainable food policy has been proposed: to reduce emissions by modernization of industrial facilities and better waste management, to organize land use depending on the contamination levels, and to reduce the bioavailability of the toxic elements.

Ecological risk assessment and long-term environmental pollution caused by obsolete undisposed organochlorine pesticides.

Obsolete organochlorine pesticides (OSPs) are currently prohibited as persistent organic pollutants that contaminate the environment. If undisposed, they continue to pollute soil and water, to accumulate in the food chain and to harm plants, animals and the human body. The aim of the study was to assess water and soil pollution around the storehouses of undisposed, banned OSPs and their possible genotoxic effect. The storehouses in four villages near Almaty, Kazakhstan were investigated. Chemical analysis confirmed contamination of water and soil around storehouses with OSPs. The genotoxic effect of water and soil samples was evaluated using model objects: S.typhymurium, D.melanogaster, sheep lymphocytes cultures and human lymphocytes cultures. It was found that water and soil samples caused mutagenic effect in all model systems. They increased the frequency of revertants in Salmonella, the frequency of lethal mutations in Drosophila chromosomes, and the frequency of chromosome aberrations in cultures of human and sheep lymphocytes. Although a genotoxic effect was demonstrated for each of these models, various models showed different sensitivity to the effects of pesticides and they varied degree of response. The association between the total content of OCPs in soil and the level of mutations for different model systems was discovered.

Miscanthus biochar value chain - A review.

To complete a loop of the Miscanthus value chain including production, phytomanagement, conversion to energy, and bioproducts, the wastes accumulated from these processes have to be returned to the production cycle to provide sustainable use of the feedstock, to reduce costs, and to ensure a zero-waste approach. This can be achieved by converting Miscanthus feedstock into biogas and biochar using pyrolysis and then returning biochar to the production cycle of Miscanthus crop applications in the phytotechnology of trace elements (TEs)-contaminated/marginal lands. These processes are subjects of the current review, which focused on the peculiarities of biochar received from Miscanthus by pyrolysis, its properties, the impact on soil characteristics, the phytoremediation process, biomass yield, and the abundance of soil biodiversity. Results from the literature indicated that the pH, surface area, and porosity of Miscanthus biochar are important in determining its impact on soil characteristics. It was inferred that the most effective Miscanthus biochar was produced with a pyrolysis temperature of about 600 °C with a residence time from about 30 min to an hour. Another important factor that determined the impact of Miscanthus biochar on soil health is the application rate: with its increase, the effect became more essential, and the recommended rate is between 5% and 10%. The influence of Miscanthus biochar on the TEs phytoremediation parameters is less studied, generally Miscanthus biochar produced at higher temperatures and added with higher application rates is more likely to restrict the mobility and availability of TEs by different plants. However, some published results are contradictory to these conclusions and showed absence of significant difference in TEs reduction during application of different Miscanthus biochar doses. The future experimental studies have to focus on determining the impact of a technological pyrolysis regime on Miscanthus biochar properties on TEs-contaminated or marginal land when biochar will be obtained from contaminated rhizomes and waste after the application of phytotechnology. In addition, studies must explore the influence of this biochar on TEs phytoparameters, enhancements in biomass yield, improvements in soil parameters, and the abundance of soil diversity.

Phytoremediation potential of Miscanthus sinensis And. in organochlorine pesticides contaminated soil amended by Tween 20 and Activated carbon.

The organochlorine pesticides (OCPs) have raised concerns about being persistent and toxic to the environment. Phytoremediation techniques show promise for the revitalization of polluted soils. The current study focused on optimizing the phytoremediation potential of Miscanthus sinensis And. (M. sinensis), second-generation energy crop, by exploring two soil amendments: Tween 20 and activated carbon (AC). The results showed that when M. sinensis grew in OCP-polluted soil without amendments to it, the wide range of compounds, i.e., α-HCH, ß-HCH, γ-HCH, 2.4-DDD, 4.4-DDE, 4.4-DDD, 4.4-DDT, aldrin, dieldrin, and endrin, was accumulated by the plant. The introduction of soil amendments improved the growth parameters of M. sinensis. The adding of Tween 20 enhanced the absorption and transmigration to aboveground biomass for some OCPs; i.e., for γ-HCH, the increase was by 1.2, for 4.4-DDE by 8.7 times; this effect was due to the reduction of the hydrophobicity which made pesticides more bioavailable for the plant. The adding of AC reduced OCPs absorption by plants, consequently, for γ-HCH by 2.1 times, 4.4-DDD by 20.5 times, 4.4-DDE by 1.4 times, 4.4-DDT by 8 times, α-HCH was not adsorbed at all, and decreased the translocation to the aboveground biomass: for 4.4-DDD by 31 times, 4.4-DDE by 2.8 times, and γ-HCH by 2 times; this effect was due to the decrease in the bioavailability of pesticides. Overall, the amendment of OCP-polluted soil by Tween 20 speeds the remediation process, and incorporation of AC permitted to produce the relatively clean biomass for energy.